Often referred to as "the silent killer," carbon monoxide (CO) is a colorless, odorless, and tasteless gas which, if left undetected, can kill building occupants without their ever knowing they were in danger. CO is a natural product of combustion, so any time a combustion source is located in a building, a potential for accidental CO poisoning exists. Potential CO sources include combustion heating equipment, gas ovens and cooktops, wood-burning fireplaces and pellet stoves, and vehicles in attached garages, to name a few. Data collected by NFPA indicates accidental CO poisoning in buildings is a significant life safety risk. For this reason, the 2012 edition of NFPA 101: Life Safety Code® added requirements for CO detection in certain new residential occupancies. The following excerpt from the 2015 Life Safety Code Handbook further explains the requirements for CO detection:
Section 9.12 provides a reference to NFPA 720, Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment, where such equipment is mandated by another section of the Code. It is noted that not all occupancies are required to be provided with CO detection and warning equipment. Such equipment is not currently required by the Code to be installed in any existing occupancy; its use is generally limited to new occupancies (other than certain existing health care occupancies) in which occupants might be asleep or otherwise have decreased capability of self-preservation and where vehicles, combustion equipment, or appliances are present. The occupancies requiring CO detection and warning equipment are as follows:
1. New educational occupancies (220.127.116.11)
2. New day-care homes (18.104.22.168.5)
3. New and existing health care occupancies containing fireplaces (22.214.171.124 and 126.96.36.199)
4. New one- and two-family dwellings (188.8.131.52)
5. New lodging or rooming houses (184.108.40.206)
6. New hotels and dormitories (220.127.116.11)
7. New apartment buildings (18.104.22.168)
Exhibit 9.16 is an example of a CO alarm. It is important to note that all CO detectors and alarms have a limited service life — typically about 5 to 10 years. CO detection equipment must be replaced at the end of its service life; the recommended replacement date is required by NFPA 720 to be marked on the device.
The requirements for CO detection and warning equipment are not based on safety to life from fire considerations. Rather, they are intended to mitigate the risk to building occupants posed by exposure to CO gas, which is a natural product of incomplete combustion of hydrocarbon fuels. Where combustion gases from equipment in a building (such as a fuel-fired furnace) are not properly vented, or where CO gas infiltrates a building from a space such as an attached garage, occupants are at risk of CO poisoning. CO gas is sometimes referred to as the “silent killer” because it is colorless and odorless. Without CO detection and warning equipment, its presence is virtually impossible to detect.
According to the Centers for Disease Control and Prevention (CDC)23, approximately 15,200 people were treated annually from 2001 to 2003 in emergency departments for unintentional, non-fire-related CO exposure. During 2001 to 2002, an estimated 480 people died annually as a result of such exposure. In 2005, municipal fire departments responded to an estimated 61,100 non-fire CO incidents where CO was present.24 The cold weather months of January and December are the peak months for non-fire CO incidents, and 89 percent of non-fire CO incidents took place in the home.
NFPA 720 is formatted much like NFPA 72, National Fire Alarm and Signaling Code, and contains requirements for CO detection systems (analogous to fire alarm systems), as well as single- and multiple-station CO alarms (analogous to smoke alarms). It was first published in 1998 under the title Recommended Practice for the Installation of Household Carbon Monoxide (CO) Warning Equipment. In 2005, it was revised as a standard; however, its scope was still limited to dwelling units. For the 2009 edition, the scope of NFPA 720 was significantly expanded to include occupancies other than residential dwelling units. The expanded requirements were based on the Fire Protection Research Foundation report Development of a Technical Basis for Carbon Monoxide Detector Siting Research Project.25 Where NFPA 720 is applied via adoption of the Life Safety Code, and where the occupancy chapter requirements of this Code differ from the requirements of NFPA 720, the requirements of this Code should apply. Where both this Code and NFPA 720 are separately adopted and enforced, the more stringent requirements should be followed so as to meet the minimum requirements of both documents.
Exhibit 9.16 - Carbon monoxide alarm. (Copyright Danny Hooks, Dreamstime.com)